ON THE CRANIAL CHARACTERS OF LACERTA JACKSONI. 19 



loG. cit.), together with 5 more individuals reared since, we find 

 that the old male no. 19 SB was undoubtedly | WW | N (W) and 

 the female was the same ; consequently all birds bred from this pair 

 should be webbed in | and a quarter of them webbed in |. As a 

 matter of fact, out of 10 birds, 1 is normal in |, 3 are webbed 

 in |, and one has all fonr toes f idly loehhed. 



It is unnecessary, therefore, to follow up the matter further, as 

 slight deviations appear in almost every mating. 



We must, therefore, be driven back to the suggestion that 

 a factor composed of two parts (cryptomeres), one of which is 

 contained in each strain, causes the web to be suppressed or 

 concealed. 



On this assumption none of the results attained are at variance 

 with the Mendelian theory. The proportions, however, do not 

 fit in, but as the numbers are small this does not count for much. 

 On the average the extent of the webbing shows a tendency to 

 diminish and the foot to approximate to the normal as compared 

 with birds of either of the pure strains, and in only one bird, bred 

 in Exp. 9, has the web included the hallux. 



Owing to lack of space and pressure of other experiments, I 

 do not propose to pursue this inquiry further, but should anyone 

 wish to follow it up I shall be very pleased to place all my material 

 at his disposal. 



My best thanks are due to Mr. Smalley, who has not onl}'- 

 supplied me with full and accurate particulars from his pedigree 

 book, but has also during the past year kept and bred many of 

 the birds in his lofts. 



2. Notes on the little-known Lizard Lacerta jacJcsoyii Blgr., 

 with Special Reference to its Cranial Characters. By 

 Edward Degen, F.Z.S, 



[Received September 15, 1910: Read November 15, 1910.] 

 (Text-figures 5-7.) 



Through the kindness of Mr.G. A. Boulenger, F.R.S., V.P.Z.S., 

 a series of seven specimens of Lacerta jacksoni has been placed 

 in my hands for investigation. These specimens, recently pro- 

 cured by Mr. R, Kemp at Mumias, Mount Elgon District, 

 British East Africa, at an altitude of 7000 feet, reached the 

 British Museum in a bad state of preservation ; opportunity was 

 therefore taken to submit the cranial structure of this little- 

 known species to a careful examination, the results of which are 

 now placed on record. 



Of the seven specimens six were males and one female. 



The specimens from which the skulls were prepared were a 

 small, but quite adult male, measuring 70 mm. from snout to 

 vent, and the single female, measui-ing 68 mm. The dimensions 



2* 



